The way the insulation boards are fixed to the subfloor depends on the base type. On a concrete base, the insulation boards are put down with a suitable flexible tile adhesive. The boards should be laid with staggered joints and once the flexible tile adhesive hardens, the joints should be re-enforced with glass fibre tape. On a wooden subfloor, the insulation boards should be put down with a suitable flexible tile adhesive and as with concrete subfloors, the insulation boards should have staggered joints. When the adhesive has set, but not necessarily dried completely, the boards should be fixed using wood screws and washers. The insulation boards should be screwed down at 200mm centres, the screw washer fixing needs to be tightened into the board until the screw head is flush with the surface. After, the joints should be re-enforced with glass fibre tape.

Although not always a necessity over wood subfloors, insulation will still greatly increase the response rate and overall efficiency of all underfloor heating systems. When installing heating over a concrete subfloor a suitable insulation must be installed as un-insulated concrete will drain the heat from the heating system.

We recommend using Living Heat Tile Backer Boards. They are availible in 6, 10, 20 & 30mm thickness. They are designed to insulate and resurface walls and floors. They are fixed in place with a flexible adhesive (on floors) and screws and washers (on walls). As well as being a superior insulation for underfloor heating, they are the perfect choice for wetroom & bathroom walls.